Thursday’s deadly shooting in Christchurch was the first mass shooting in Oceania since the 1996 mass shooting in Port Arthur, Tasmania that killed 35 people. A 22-year span that international security expert, Christian Leuprecht, says may have caught New Zealand law enforcement of guard.

“One way to demonstrate this is that this attack is an outlier and that New Zealand has not had the challenge of this type of attack or a police raid to take out this attack,” said Leuprecht.

Leuprecht said the rarity of this incident is either because the New Zealand authorities are doing a fantastic job thwarting or keeping dangerous people who are capable of this attack out of the country, or perhaps authorities underestimated this threat.